Monoamides of dicarboxylic acids and process of preparing the same



Patented Dec. 7, 1937 UNITED STATES PATENT OFFlCE MONO AMIDE S OFDICARBOXYLIC ACIDS AND PROCESSOF PREPARING THE SAME Paul L. Salzberg,Wilmington, DeL, assignor to E. I. du Pont de Nemours & Company, Wil--mington, DeL, a corporation of Delaware No Drawing. Application June 5,1936,

Serial No. 83,811

9 Claims.

This invention relates to new compounds and new compositions of matter,and more particularly to monoamides of dicarboxylic acids having one ofthe amido hydrogens replaced by an aliphatic hydrocarbon radical of atleast 8 carbon atoms and alkali and alkaline earth metal salts of theseamides.

These compounds have the general formula CN R R:

000x in which X is hydrogen or an alkali or alkaline earth metal, Rrepresents the residue of a dicarbcxylic acid, preferably anortho-aromatic radical of the benzene series, R1 is an aliphatichydrocarbon radical containing eight or more carbon atoms, and R2 ishydrogen or'an organic radical. The invention especially relates tophthalamates of long chain amines, that is, to

sure plasticizers for cellulose derivatives. An-.

other object is to produce new and useful wetting agents and detergents.Other objects will appear hereinafter.

In accomplishing these objects in accordance with the present invention,it has been found that compounds having the general formula in which Rrepresents the residue of a dicarboxylic acid such as phthalic acid, R1is an aliphatic hydrocarbon radical containing eight or more carbonatoms, and R2 is hydrogen or an organic radical, may be prepared byreacting long chain primary or secondary aliphatic amines containing atleast eight carbon atoms with acid anhydrides such as phthalicanhydride, or by hydrolyzing long chain imides of acids such as phthalicacid and isolating the resulting products. Thus, when long chain primaryamines containing at least eight carbon atoms are reacted with phthalicanhydride, the phthalimide may be obtained as an intermediate. This isconverted to the phthalamate by hydrolysis, e. g., with an aqueousalkaline solution. Long chain secondary amines containing eight or morecarbon atoms react with phthalic anhydride to give the long chainphthalamate directly.

The invention will be further illustrated by the following examples inwhich the quantities are stated in parts by weight.

Example I Forty parts of monododecyl amine and 32 parts of phthalicanhydride were heated at 180-200 C. for one hour forming theintermediate dodecyl phthalimide. This product, without isolation, wastreated with a 10% KOH solution for half'an hour and the aqueoussolution was strongly acidified with hydrochloric acid. 'Theprecipitated crude product was crystallized from ethyl alcohol to yield30 parts of monododecyl phthalamate, melting at 88 0.

Example II Forty (40) parts 01' didodecyl amine were heated with 16.8parts of phthalic anhydride at 220 C. for five hours. The product,dissolved in benzene, was treated with decolorizing carbon and thesolvent allowed to evaporate from the filtered solution. Forty-two (42)parts of didodecyl phthalamate, a brown viscous oil, were obtained.

Example III Fifty (50) parts of mono-octyl amine and 57.5 7

parts of phthalic anhydride were heated at 150 C. for fifteen minutes.The reaction mixture was recrystallized from 300 parts of ethyl alco holto yield parts of octyl phthalimide melting at 50-51 C. Octylphthalimide was treated with 10% KOH for half an hour and the aqueoussolution strongly acidified. The precipitated crude product wascrystallized from 50% ethyl alcohol to yield mono-octyl phthalamate.

Example IV One hundred fifty parts of potassium phthalimide was treatedwith 10% KOH for half v an hour and the aqueous solution stronglyacidified. The precipitated crude product was crystallized from 50%ethyl alcohol to yield mono-octyl phthalamate.

Example V To 9.8 parts of maleic anhydride dissolved in ether were added37.2 parts of dodecyl amine dissolved in ether, and the reaction mixturerefluxed. The reaction product obtained after recrystallization fromalcohol was a white solid melting at 98 C.

Example VI To 92.5 parts of dodecyl amine were added slowly, withstirring, 74 parts of phthalic anhydride, keeping the temperature under50 C. The reaction product was dissolved in an excess of sodiumhydroxide, the solution acidified, the precipitate filtered and dried.An 81% yield of a product identified as monododecyl phthalamate wasobtained.

' Example VII To 59 parts of a mixture of octadecyl and cetyl amineswere added 34.4 parts of phthalic anhydride, and the mixture heated withstirring at 60 C. for two and one-half hours. The reaction product,after crystallization from acetone, was a crystalline solid melting at91-95 C.

The compounds prepared in the manner described above are whitecrystalline solids or oily liquids. They are substantially insoluble inwater but are soluble to varying degrees in organic solvents.

Instead of the amines used in the examples, other amines may besimilarly employed including monoalkyl amines, e. g., nonyl. decyl,undecyl, tetradecyl, cetyl, octadecyl, 9: 10-octadecenyl, and eicosylamines; dialkyl amines, e. g., dioctyl, dinonyl, didecyl, diundecyl,ditetradecyl, dicetyl, di-(9,10-octadecenyl), dioctadecyl amines; mixeddialkyl amines, e. g., methyl octyl, propyl dodecyl, butyl octadecyl andmethyl octadecenyl amines. As further examples of secondary amines whichmay be employed may be mentioned N-dodecylaniline, N-dodecyl-glucamine,and Ndodecylethanolamine.

In carrying out the reaction, substituted phthalic anhydrides may beemployed as, for example, those containing halogen (e. g., chloro-,fluoroor bromo-) nitro, or sulfonic acid groups. As further examples ofacid anhydrides which may be reacted with amines in accordance with theinvention may be mentioned hexahydrophthalic, adipic, succinic, pimelicand itaconic anhydrides. In general, anhydrides of dicarboxylic acidsforming inner anhydrides, and especially phthalic anhydride, itsanalogues and homo logues, are preferred. 7

The proportions of amine and acid anhydride may vary, but generally goodresults are obtained with approximately equimolecular proportions.However, an excess of either reactant may be used.

The temperature of the reaction is subject to variation depending uponthe particular reactants, but generally speaking I can operate in oneway of two ways. In carrying out the reaction in one step with a primaryamine and phthalic anhydride, I prefer to operate between thetemperatures of 30 C. and that temperature at which the 'phthalamic acidis converted into the phthalimide. If thereaction with a primary amineand an acid anhydride is to be carried out in two steps, I prefer tooperate in the range of about C. to about 225 C. In the reaction betweena secondary amine and an acid anhydride I prefer to operate at atemperature range of about 150 C. to about 225 C. If desired, higher orlower temperatures may be employed. The reaction may be carried outunder atmospheric or superatmospheric pressures.

If the reaction between a primary amine and an acid anhydride is carriedout according to the second method, the hydrolysis of the imide may beeffected with an aqueous hydrolyzing agent as, for example, an alkalimetal hydroxide such as an aqueous solution of sodium hydroxide orpotassium hydroxide. If the acid is desired, the final product isfurther acidified.

The reaction between the amine and the acid anhydride and/or thesubsequent hydrolysis may be effected in the presence of a solvent ordiluent, e. g., benzene, acetone, mineral spirits, dioxane, toluene,cyclohexane, hexahydroand decahydronaphthalene.

Inasmuch as the resulting product contains a carboxyl group, it iscapable of forming salts by the addition of inorganic bases, e. g.,potassium carbonate, sodium hydroxide, potassium hydroxide, calciumhydroxide, and the like.

The invention provides new and useful waterresistant, low-vapor pressureplasticizers for cellulose derivatives. The alkali metal or amine saltsof the long chain compounds show advantageous wetting and detergentproperties.

The phthalamates of the long chain mines in particular are very useful.Among their specific uses maybe mentioned their use as plasticizers inconjunction with cellulose derivatives such as cellulose nitrate, ethylcellulose or cellulose acetate, in the preparation of lacquersandenamels for coating wood, metal, fabrics, cloth, paper and wirescreens, in dopes for coating fabrics, in moisture-proofing lacquers forcoating regenerated cellulose and related substances, and in plasticcompositions used for the manufacture of toiletware, sheeting, rods,tubes and dentures. Due to the non-volatile nature of these compounds,films of cellulose derivatives containing them are substantiallypermanently flexible and have good durability.

The phthalimides of long chain amines which are intermediates in thepreparation of phthalamates may be isolated and are useful asplasticizers for cellulose derivatives. In moistureproofing lacquers forregenerated cellulose, the phthalimides yield a product of goodappearance which possesses favorable moisture-proofing characteristics.

In the form of their alkali metal or amine salts the phthalamates oflong chain amines may be used as wetting agents, detergents, mercerizingassistants, emulsifying agents, pigment dispersing agents, flotationagents, insecticide spreaders, and for similar purposes where surfaceactive materials are desired.

As many apparently widely diiferent embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined in the appended claims.

I claim: 1. Compounds having the general formula 0 R1 ll R R1 oooxhydrogen. alkali metals and alkaline earth metals. It represents theresidue of a dicarborylic acid, R1 is an aliphatic hydrocarbon radicalcontaining at leasteightcarbonatomaandlhisamemberot I the classconsisting of hydrogen and alkyl radicals.

2. compounds having the general formula COOX coon in which R1 representsan aliphatic hydrocarbon radical containing at least eight carbon atoms,30 and Re is a member of the class consisting of drogen and alkvlradicals.

. Compounds having the general formula 2,101,323.Pwl L. Salzberg,Wilmington,

Acme am: Paocnss or Panmame ran Disclaimer filed Jan. 8, 1946, by theassignee,

Mmv" I O I Haebyentersthisdisclaimertoclaimsl andEmthespecrficatron.

[Qficial Gazette Fdmm'y 12, 1946.}

g N Bi Ba COOK in which R1 represents an aliphatic hydrocarbon radicalcontaining at least eight carbon atoms, and R2 is a member of the classconsisting of hydrogen and alkyl radicals, the step which comprisesreac'ting an anhydride 01' a dicarboxylic acid with a long chainaliphatic amine containing at least eight carbon atoms and having atleast one hydrogen atom on the amino-nitrogen.

6. The process which comprises reacting, by heating, phthalic anhydridewith an aliphatic amine containing an aliwl radical of at least eightcarbon atoms.

7. The process which comprises reacting, by heating, phthalic anhydridewith a primary aliphatic amine containing at least eight carbon atoms,and treating the resultant product with a hydrolyzlng agent.

8. The process which comprises reacting, by heatin phthalic anhydridewith a long chain aliphatic secondary amine containing an alkyl radical01 at least eight carbon atoms.

9. The process which comprises reacting, by

E heating. phthalic anhydride with a long chain as aliphatic aminecontaining an alkyl radical of at a m least eight carbon atoms andhaving at least one hydrogen atom on the amino-nitrogen at a temperaturewithin the range of about 150 C. to

inwhichR-i representsanaliphatichydrocarbon about 225'0. 4|)radicaloontainingdghttoeighteencarbonatoms, PAUL L. BAIEBERG. at

D l S C L A I M E R Del. Monomnns or Drcaasoxrmc Sum. Patent dated Doe.I, 1937. E. I. du Pont de Nemours and 2,101,323.Pwl L. Salzberg,Wilmington,

Acme

hydrogemalkalimetalsandalkalineearthmetals. and R: s a member of e classconsistin o It represents the residue of a dicarborylic acid. R1 hydrsen and dbl radic is an aliphatic hydrocarbon radical containing at 5.In a process oi producing having least eight carbon atoms, and R: is amember oi the general formula I the class consisting of hydrogen andalkyl radi- E N m 5 cals.

2. compounds having the general formula o a. I. /& N\ COOK 10 B B. inwhich R1 represents an aliphatic hydrocarbon \coox radical cigntainingat least eight carbon atoms, and R: a member of the class consisting 0!3323.131? 223E532 521? t at hydrogen and the M II R is g mithmmmmcradical of the benzene prises reacting an anhydride 01' a dicarboxyllc1s flea R1 is an aliphatic hydrocarbon radical com acid with a longchain aliphatic amine containtfl it least eight Mn atoms and R: is a ingat least eight carbon atoms and having at least one hydrogen atom on theamino-nitrogen. m g rg i class of hydrogen 6. The process which compises reacting, by

.0 heating, phthalic anhydride with an aliphatic m compound men! 10mmamine containing an allwl radical of at least eight 0 carbon atoms. E 7.The process which comprises reacting, by

heating, phthalic anhydride with a primary alill phatic amine containingat least eight carbon 86 C003 atoms, and treating the resultant productwith a hydrolyzlng agent. sie wressszzna ewzsztem m mm which comm byheatins. phthalic anhydride with a long chain aligo and Re is a memberof the class consisting of a men and ml Mum phatic secondary aminecontaining an alky radicompounds mm me new fo ula cal 01 at least eightcarbon atoms. 0 R1 9. The process which comprises reacting, by aheating. phthalic anhydride with a long chain as aliphatic aminecontaining an alkyl radical of at a m least eight carbon atoms andhaving at least one hydrogen atom on the amino-nitrogen at a tem- COOHperature within the range of about 150 C. to inwhichR-rrepresentsanaiiphatichydrocarbon about 225'0. 4|) radicalcontainingdghttoeighteen earbonatoms, PAUL L. as

D l S C L A I M E R Del. Monomnns or Drcaanomrc Paocnas or Panmamo'rnnSum. Patent dated Dec; I, 1937.

m DisclaimerfiledJan. 8, 1946, bythe Company.

, E. I. du Pont de Nemours and entersthisdisclaimertoclaimslandSinthespeeification. [Qficial Gazette Fdmm'y 12, 1946.}

